Fluid pumping and mixing device



- y 1933. w. CARTER 1,906,740

FLUID PUMPING AND MIXING DEVICE Filed March 2. 1926 2 Sheets-Sheet 1 Fig. I.

WITNESSES I INVENTOR May 2, 1933..

. w. D. CARTER FLUID- PUMPING AND MIXING DEVICE Filed March "2, 1926 2 Shets'-Sheet 2 INVENTOR WITNESSES Patented 7 May 1933 UNITED STATES.

PATENT; OFFICE- WILLIAM FOUGLAS CARTER, OF CALDWELL, NEW JERSEY, ASSIGNOB, '10 CARRIER CORPORATION, 01' NEWARK, NEW JERSEY, A CORPORATION OI DELAWARE mm ruxrmcann mixme DEVICE Application and Karen 2, 1926. Serial No. 91,712.

This invention relates primarily to rotary positive dis lacement gas compressors having a liqui seal, and pertains particularly to that class of pumps having a central ro- 5 tary member or wheel eccentrically mounted with respect to the casing in which a sealing fluid, such as water, is employed to draw in or compress a lighter fluid, such as air,

between the wheel and the casing.

Since the maximum gas pressure obtainable in this t pe of pump cannot exceed the pressure of t e sealing liquid and since the pressure of the sealing liquid depends largely upon its rate of rotation, it is important that the rotation of the sealing liquid be maintained efficiently with a minimum ofslip and friction loss.

Certain features of this invention may also be applied to pumps in which the mechanical parts cooperate so closely as to make a liquid seal unnecessary, but its application to-a liquid-seal type of pump in which the seal acts as a liquid piston, will be described in this specification.

5 Inthe preferred construction of this pump both the wheel and the casing are made to revolve with the sealing liquid so that the fluid friction is reduced to a minimum. Se arate means are provided for umping t e sealing liquid to the :casing; or expelling surplus liquid from the casing; and for carryingaway the heat generated in compressing the gas. v

' While this pump is used most frequently for compressing agas such as air, with a liquid seal, it is possible to employ two liquids or two gases of different specific gra'vlties-the heavier fluid acting the sealin fluid. For instance watercould be pumpe 40 using mercury as a sealing liquid, anda high pressure obtained with comparatively 7 little friction loss. The pump may also be adapted, with some modification, to operate in a horizontal shaft osition.

The construction illustrated has special features which adapt it particularly to use in connection with oil burners wherein a vsmall quantity of oil, comprising the sealing liquid, is mixed with a-much larger quantity-i of air and discharged 11 'means for nder pressure into the furnace. This loss of oil is made up throu h the special means provided to entrain addtionai oil into the pump.. Other uses will be apparent. One of the avoid turbulence and slip by drivin both the wheel and easing at the same speed.

Another object is to provide automatic means for gradually supplying the sealing fluid to the casing when starting the pump,

so as to avoid turbulence and splash in bringing the fiuid up to speed.

' Another object is to provide a simple means for cooling the pump by circulating air against the outside of the rotating casing.

Another object is to provide adjustable discharging a proportion of the sealing fluid as a spray with the lighter fluid, without resorting to throttling restrictions likely to clog;

Another 0 ject is to provide a wheel with separate passages for pumping the two different fluids at the same time.

Another object is to control the performance of the pump by varying the eccen tricity of the wheel in the casing.

Another object is to avoid the friction and leakage of stufiing boxes.

Further objects will appear.

This invention consists of the parts and the construction and combination of parts as hereinafter more fully described and claimed, having reference to t e accompanying drawin s, in which igure I is a longitudinal cross-section of p the pump taken on line A-A of Fig. 2.

- Figure II is a plan view of the construction shown in Fig. I taken along line BB, and

having. the upper part of the case and the housing of the blower removed.

Figure III is a perspective view of the impeller- 'the top view of which is shown in Fig. II, and a cross-section in Fig. I.

Figure IV is a plan view ofthe distributor,

also shown in transverse section in Fig. II,

and in longitudinal section in Fig. I.

objects of this invention is to,

Figure VII is a top view of the assembled unit. a

Figure VIII is a 'top view of the burner oil-supply scoop, feature.

Figure IX is a bottom view of the reservoir part of the casing showing the radially disposed vanes whic form part of the impeller of the air coolin fan or blower.

Referring to t e drawings in detail, 1 is a vertical motor shaft upon which is mounted the rotating reservoir casing 2, which carries on its underside radially disposed vanes or ribs 3. Reservoir plate 4 closes the top of reservoir 2 but has holes 5 near the center of the plate for admitting liquid to the reservoir, and smaller holes such as 6 nearer the periphery of the plate to allow the liquid in the reservoir to escape slowly by centrifugal force when the reservoir is started in rotation.

Obviously, holes 6 also permit some of the liquid to return to the reservoir when rotation stops, but their chief'object is to supply the liquid gradually to the rotating casing 7 so as to avoid splash and turbulence in bringing the liquid up to speed. Reservoir.2 has a shallow passage 8 connecting with holes or conduit openings 6. Plate 4 carries a number of posts or blades 9 which serve to minimizethe slip and to make the sealing liquid rotate with casing 7.

Line 10 represents the inner cylindrical surface of the sealing liquid when the casing 7 is rotating. Hole 11 is concentric with casing 7, and 1s smaller thanthe circle of line 10 so that the liquid will not spill out when the pump is running. The liquid will fall away rom opening 11 by gravity when the pump comes to rest, and will assume a horizontal level below the top face of wheel 14.

If, in any given installation, the liquid supply and return pipes 31 and 32 should be carried downward to a liquid supply tank beneath the level of the pump, there would be a tendency to siphon'the liquid from the casing 7 when the pump stops operating; but owing to the fact that the sealing li uid in the casin falls below the top face 0 wheel 14 and elow scoo 38, air will enter at these oints and there y prevent any loss of sealing liquid below'these evels.

Radially disposed vanes or ribs 12. (see Fig. I) are attached to casing 7, similarly to vanes 3 on reservoir 2 (see Figs. I and IX). These vanes 12 together with vanes 3 are enclosed. within the housing 13 and housin cover 50, which cover is attached at 51 (Fig. VI to stationary frame 37. These vanes an housing constitute an air pump or fan for drawing air along the surface of casin'g,7 and reservoir 2, so as to carry away the heat of compression nerated within casing 7. 47 (Figs. VI antf VII) is the discharge opening'of the fan and arrows 48 and 49 indicate the inlet openings thereto.

illustrating its adjustable 52 represents the motor drivin eel having radia y disposed pockets 15 formed between its two side discs and the radially dis osed arms 18. Some of the arms 18 have oles 19 extending radially from theperiphery to connect'with other but axially disposed holes 20 in the hub. Said holes 20 are arranged on a circle close to, wheel.

Arranged on a larger circle, also concentric with the axis of wheel 14, are a number of other holes 16 extending through the hub and running parallel to the axis of the wheel. This last set of holes register with the port 21 in distributor conduit-member 22; and simultaneously, at-the bottom of the wheel, with channel 23 in the flange 24 of hollow! axle 25. Various other forms of conduit-members can be adapted to convey fluid to or from. the wheel.

All of the holes 16 in this circle also registerat intervals with port '46 in distributor 22 but no flow is established through holes 16 at thattime for the reason that holes 16 are then closed at their wer ends by dang: 24. Air reaches port 46 hrough openin aid holes 20 register with ports 26 and 27 (see Figs. II and IV) in distributor 22, and thereby connect radial holes 19 with said ports 26 and 27- at predetermined intervals in each revolution of the wheel. Opening 55 connects port 26 with pipe 31.

Located between said holes 16 in the larger circle on wheel 14, are other holes 17 extending through the 'top of. the wheel and arms 18.

The wheel 14 is mounted on ball-bearing 28 which is held in the'hub by means of threaded collar 29, and carried by axle 25 which is rigidly attached by means of nut 30 to the distributor 22.

Distributor 22 is supported by the three pipes 31, 32and 33 held in-bracket 34 which .connecting with pockets 15 between the.

is slidably attached b means of screws 35 Y and 36 to frame 37. T ispermits adjustment of the eccentricity'of the axis of wheel 14 with respect to the axis-of casing 7.

31 is a pipe for supplying sealing fluid to the pump. 32 is a return pi vfor conveying any surplus sealing fluid ack to the source of supply. 33 is the main air discharge pipe w ich, in the service herein described, conveys a spray or fog of oil and air from port 21, through opening 56 to the burner nozzle 53.

Distributor 22'carries 38' which connects through opening 39 (see Fig. IV) with return pipe 32, and prevents the accumulation of liquid in casing 7 in excess of the rotating surface indicated by line 10. Scoop 38 constitutes a simple preferredform of pumping element for returning exthe overflow scoop cess oil to the source of supply, just as the im eller constitutes apumping element of a di erent type for supplying oil to the easing.

is a connecting rod pivotally attached at 41 to one. of the posts 9, and to the spring 42 which is in turn attached to wheel 14 at screw 43. The purpose of this rod and spring is to transmit rotation from casing 7 to wheel 14,-the s ring serving to compensate for the adjusta le eccentric mountmg of easing 7 with respect to wheel 14 so. as to transmit rotation smoothly from the casing to the wheel. In order more effectively to transmit uniform rotation to the wheel, wings 44 are provided on the sides of wheel 14 to receive the impulse of the revolving liquid and thereby counteract the varying angle of pull from the spring due to the eccentricity of the two connected members.

The adjustable spray scoop 45 receives the impact of the sealing liquid and maintains fluid pressure in channel 23 with which it is connected. The axle 25 is provided with a slot in its upper end, as shown in Fig. 1. A

key or screw driver inserted in this slot en-' ables axle 25 to be rotated, whereupon flange 24 and scoop 45, fixedly attached to the axle will be turned. By rotating the axle 25, the scoop 45 can be subjected to a lower veloclty of liquid, since the axle 25 is not concentric with the axis of rotation of the liquid.

. The full lines in Fig. VIII illustrate the high tion and stoppage therein.

pressure position of the scoo I passing through the scoo passages is very small, t e

.the rotating casing 7, which it 45, and the dotted lines show its position w en rotated nearer to the center of the whirling ring of sealing fluid. Although the 45 and connecting intermittent nature of the flow effectively prevents coagula- For many services the pump would be required merely to compress a gas without injecting a spray of the sealing liquid into the discharged gas. and usually'scoop 38 are not required. I

While the use of this pump is by no means confined to its connection with oil burners, the construction shown is particularly adapted to that service'an'd its operation W111 therefore be describe in that application.

Supply pipe 31 is connected with the oilsupply tank which is not shown and which will be assumed to be located somewhat lower than the pump. Return pipe32 conveys surplus oil from return scoop 38 back to the'supply tank. The pump is ervoir 2 with furnace oilfwhich is used as the sealing liquid.

VXhen rotation 3081118 this oil in reservoir 2 is t re 11 outwar roug passage 8 as ast as it c131 flow through the small holes 6 into adually fills to approximately the inside cy indrical surface indicated by line 10. Any surplus over in this case amount of liquid In such cases spray scoop 45' primed by filling resthis amount will obviously be returned by the revolving oil. are rotating at approximately the same speed.

Since the rotating ring of oil in casing 7 is not concentric with the rotating wheel, it is obvious that there will be a relative radial motion between the oil and any given point on the wheel. That is, during one half of each revolution re resented b the position of the parts shown a We line --A in Fig. II (when the pump is rotating in the direction indicated by the arrows) the oil is receding from the pockets 15; and during the other half (below line A-A) the oil is entering sai the pockets 15 and the holes 17 are in register with port 46 in distributor 22, air is entrained into the pockets.

During the other half revolution this airckets. When the oil is receding from is compressed as the oil presses toward the.

center of the wheel 14; and air-is discharged under pressure through openin 56 and pipe 33 to the burner nozzle 53 when oles 17 come into register with discharge port 21.

B loosening screws 35 and 36 and moving racket 34, the eccentricity of wheel 14 incasing 7 may be varied. This changes the depth to which pockets 15 di into the ring of oil and consequently the v0 ume of air dis? placed.

In the meantime oil pressure is maintained in channel 23 by means of adjustable scoop 45, and small quantities of this oil are in- ,jected intermittently into the stream of air passing out of discharge port 21, while the oles 16 in passing, temporarily connect port 21 with channel 23.

The amount of oil injected into. thedischarged air may obviously be varied by rotating the axle 25, and with it scoop 45 and channel 23 as shown in Fig.'VIII. This adjustment not only changes the oil pressure in the channel 23, but also varies the time interval during which channel 23' is connected with discharge port 21. Thus the amount of oil supplied to the burner may be adjustedwithout resorting to small throttled orifices which are'likely to clog.

In the meantime the oil fed to the burner from casing 7 is b'ein replenished from the oil-supply tank (not s own in the drawings) as follows: i

Centrifugal force acting on the oil in holes 19 of wheel 14 tends to causethis oil to flow toward the periphery of the wheel and to min le with the whirling ring of oil in casmg This flow can take place (under ordinary speeds of rotation) only when holes 20 register with port 26 in distributor 22, for at eccentrici I v ring of o will. draw the air into holes 19.

m and will expel said air by these air leakages so lon to the burnernozzle 53.

In cases where it is desirable to supply auxthe air discharge that time holes 19 can be filled at their central ends from the storage tank through pipe 31, opening 55, port 26.

If pipe 31 should be full of air instead of 3 oil when the pum is started, thenvthe reciprocating action of t e oil in'holes 19 (due to the of the wheel and the whirling when holes 20 are in register with port 26,

rom holes 19 when holes 20 connect with the atmosphere through port 27. This priming action is the same as that which takes place when air is entramed compressed, and expelled by the pockets of wheel 14, as previousl described.

It will 'be noted t at any air entering through pipe 31 while the pump is pruning itself, or entering in small bubbles from leaks in the. pipe connections, or throng1 types of anti-siphon devices wlnc certain may be connected in the suction line, will be separated from the oil in the casing by oentrifu action, and so the feeding of oil to the urner nozzle through scoop will not be affected as the average e source of sup quantity of oil drawn from ly' is adequate for the requirements of the urner. Usually the amount of oil circulated is many times greater than the quantity fed iliary air'to a furnace under a ,V

47 (see'Figs. I and VII) from the cooling fan, may be connected to. the fire-box. Th may also be connected to the air inlet opening 54 in distributor" 22.

Where the expression umpin element is used in the claims, it wi be un rstood to mean-one of the main cooperating parts of a pumping mechanism without which no pumping action would result.

That which I claim as my invention and desire to secure by Letters Patent is:

1. In; an oil feeding mechanism for oil burners, the combination of an oil pressure means, a discharge conduit communicatin with the pressure means, a valve in the pa of the conduit, automatic means for o n' and closing the valve in a repeating cyc e,'an controlling means for adjusting the period of time during which the valve remains open so as to control the amount of oil supplied itive head,

through the conduit.

- adapted to rotate in the same direction as the oil and alternately to advance into andwithdraw through the free surface of the oil so as to fill and empty the'pockets and thereby alternately to expel and suck air through the 06 ports, a stationary conduit member co-ppe pressure created by this fan,

crating with the wheel to convey air from the ports, and adjustable means for dischar ing with the air a controlled amount 0 011 thro h the conduit member.

3. l n an oil feeding mechanism for oil burners, a casing for holdin a revolving ring of oil, a wheel havin poc ets with communicating ports formef therein, the wheel being adapted to'rotate in the same direction as the oil and alternatel to advance into and withdraw through the ree surface of the oil so as to fill and empty the pockets and thereby alternately to expel and suck air through the ports, a stationary conduit member co-operat' mg with the wheel to convey air from the ports, adjustable means for discharging with the air a controlled amount of oil through the conduit member, and a separate oil supply conduit communicating with the casing.

4. In a rotary pump for oil burners, a casingfor holding a whirling ring of oil therein, a pocketed wheel eccentrically mounted to rotate in the casin so as to sink more deeply into the ring 0 oil on pne side than on the other and thereby to displace and entrain air from and into the pockets, the wheel also having a set of radiall disposed passages formed therein forcentrizugally entraining oil into the casing, a stationary distributor member cooperating with the wheel and having separate ports formed there'n cooperating with ports fdrmed in the wheel for conveying air to and om the .pockets and oil to the passage.

5. In a rotary pump aving a casing mounted to rotate on a vertically disposed axis, a partition located in the casing normal to the axis thereof so as to divide the interior of the casin into an upper pumping compartment and a lower reservoir compartment, the partition having formed therein a renear their periphery so as to permit fluid to flow by centrifugal force from the reservoir compartment to the umping compartment when rotation begins in order to supply fluid gradually to the pumping compartment.

6. In a device for producing a mixture of combustible liquid and air, the combination of an eccentric air-pump of the liquid-piston type utilizin 'a combustible li uid as the liquid element t ereof, an air disc t means for feeding a uniform amount of liquid from said li uid element of the aippump to the conduit or mixing with the .air output thereof as the combustible constituent of said mixture discharged, and automatic liquidsupply means for, maintaining the full vol-' ume of said liquid element.

7. In a rotar pump, a rotatably mounted casing for revo vmg a sealing fluid contained therein, a wheel having pockets with connecting ports forme'dtherein and adapted to rotate in the same direction as the sealing fluid,

said wheel being'ecoentrically mounted in' the urge condui of rotation eccentric to the axis of rotation of the wheel, air impelling vanes attached to the outside wall of the casing, a second stationary casing surrounding the vanes on the first casing, t e stationary casing having an air inlet and a discharge opening formed therein for conveying air to and fromthe vanes between the first and second casings.

9. In a pump for oil burners, a rotatably mounted casing for whirling a ring of oil, a

. wheel with communicating pockets and ports formed therein, the wheels being eccentrically mounted to rotate in the casing so as to dip more deeply into the oil on one side than the other in order to expel and draw air from and into the pockets, distributing means cooperating with the ports in the wheel for conveying air from the wheel and a stationary conduit with one end directed against the whirling oil and the other end communicating with the distributing means so as to convey oil from the casing to the distributing means. I

10. In a pumping mechanism of the character described, a casing for holdin a revolving ring of liquid, a supply line or conveying liqu1d from a fuel sourceto the ring of liquid in the casing, a discharge line for returning liquid to said source from the ring of liquid in the casing, a feed line for discharging liquid to a burner fromthe ring of liquid in the casing, and means for maintaining the thickness of said .ring of liquid substantially constant.

11. In an automatic valve for oil burners,

the combination of an entrance-head and a discharge-head, each head having a smooth surface of revolution with an arcuate channel formed therein about the axes of said surfaces and an opening in each head communicating with its respective channel, a rotatable disc member located intermediate of the entrance-head and the discharge-head and having a pair of surfaces of revolution in close co-o'pe'ration with the surfaces of revolution of the heads, all of said axescoinciding with the axis of rotation of said disc member, the disc member having formed therethrough one or more separate'passages connecting at intervals the channel of the' entrance-head with the channel of the discharge-head, means for rotating the disc member, and other means for ad3usting the relative angular ositionof the heads so as to control the time interval of the liquid and mixing it with in each revolution during which the channels and openings are in communication.

12. rotatable im eller for spray pumps eonsistln of a cylin rical shaped body havmg radla 1y disposed ockets formed in the periphery thereof an ports near the axis ofrotation communicatin with the pockets so as to convey air to an from the pockets, the bod having formed therein also separate channe s for impelling liquid to the periphery of the body.

13. In a spray pump, a casing for holding a revolving ring of 11 uid, an impeller consistin of a cylmdrica shaped body having radia ly disposed pockets formed in the periphery thereof and ports near the axis of rotation communicating with the pockets so as to convey air to and from the pockets',the

. body having formed therein also separate channels for im lling liquid to the casing. 14. A rotatab e impeller for spray pumps consistin of a cylindrical shaped body having radia ly disposed pockets formed in the periphery thereof and air ports disposed in acircle near the axis of rotation c'ommunieating with the pockets, the)body having formed therein also separate cavitles in the periphery thereof and liquid admission ports opening ina circle near the axis of rotation communicating with the cavities so as to impel liquid by centrifugal force from the admission ports to the cavities, the circular disposition of said liquid admission ports bein substantially concentric to but separated from the air ports so as separately to convey liquid from the admission ports to the cavities and air from the pockets to the air ports.

15. The method of producing a mixture of liquid and gas consistmg of rotating a liquid by means of a rotatable casing whereby an inner free cylindrical surface of said liquid is formed, compressing a gas against said surface, and continuously removinga portion t e as.

16.- In a rotary pump, a rotatable casing,

a rotatable wheel eccentricallv mounted in the casing, and mechanical yielding means connecting the casing to the wheel so as to impart uniform rotation between the casing I and the wheel.

17. In a rotary spray ump, an air discharge conduit, a rotatab e casing normally partly filled with liquid, an air-pumping im- Her mounted in the casing, the -1mpeller aving ports formed therein communicating with the conduit, means for discharging some of the liquid with the air through the conduit, and liquid supply means operatin in,

unison with the casing for delivering a ditional liquid from an external source to the casing so as to maintain a substantially constant amount of liquid inthe casing. V n

18. In a rotary pump of the class d'e- .scribed, a casing, a wheel eccentrically mounted in the casing, the wheel having ra- 45 ring of liquid, an air-pum ing im to stream of liquid to one dially disposed pockets formed in the periphery thereof and ports formed in concentr1c circles around its axis of rotationcommunicating individually with the pockets, a 18 stationary distributor a-ving ports concentrically arran ed therein co-operating with the ports in the wheel so as to convey fluid to and from the pockets in independent streams foreach ofthe concentric circles of 10 ports.

19. In a rotary pump for oil burners, a rotatable casing for whirling a ring of oil contained therein, a stationary scoo supported in the casing with one end directed against the path of the whirling oil for collecting oil, a valve in the path of the oil discharged from the scoop, and automatic means for opening and closing the valve in a repeatingncycle,

80' 20. a rotary spray pump, a casing, air pressure means in the casing, fluid suction means in the casing for drawing a mixture of liquid and air into the casing, liquid feeding means in the casing for conveying liquid '88 from the casin to the air pressure means, andf'centrifugal separating means in the casing for separating the air from-the mixture of liquid and airiso'as to furnish a uniform volume of liquid for the liquid feeding means.

arotary pump of the class described, a rotatable casing for revolving a ring of liquid'thereim'a rotatable wheel having pockets formed in the lperiphery thereof, the wheel being eccentrical y mounted in the casing so 85 as to dip into the li uid whereby a pumping action is obtained t rough themovement of the liquid in the pockets, adjusting means for varying the eccentricity of the wheel with respect to the casing, and transmission means 40 for transmitting rotation between the wheel and the casing irrespective of the adjustment of said eccentricit 22. In a rotary pump, the combination of a rotatable casing for holding a revolving the-casm a stationary ax e rotata 1y supporting-t e impeller, the axle having its axis eccentric to the axis of the casing, the axle havingan unsupported end in the casing, and

a scoo carried by the unsupported end of the a e.

23.. In a rotary pum a c sing, a wheel rotatably mounted in t e casing, the wheel having sets of assages formed therein and ports through t e w eel communicating individually with the passages, a distributor having separate ports arranged therein cooperatmlg individually with the several ports in the W eel so'as to convey independently a set of passages and air from another set of passages. 24. In a rotary pump, an air discharge coni duit, a casing normally partly filled with liquid, an air-pumping impeller rotatably mounted in the cas1ng,-the 1mpeller having other of which draws oil ller in charge means cooperating with the casing 1 and communicating with t e other liquid conduit to discharge surplus liquid from the easmg so as to mamtain-a substantially constant amount of liquid in the casing.

25. In combination, a source of oil supply, a rotating casing for holding a revolving ring of oil whichtends to assume an inside cylindrical surface, two pumping elements cooperating with the casmg whereby independent pumping services are obtained, one of which draws oil from the source of supply and delivers to the rotating casing and the from the rotating casing and delivers to the source of supply,

the inlet to the last named being located at the position in said rotating pumping element casmg at which the oil surface is to be maintalne 26. In combination, a source of liquid supply, a conduit, a rotatin casing for holding a revolving rin of liquid which liquid tends to assume a cy indrical inside surface, three pumping elements mounted within and coacting with the revolving whereby th ee independent-pumping services are obtaine one 0 which draws liquid from the source of supply and delivers to the rotating casing, anot er of which draws liquid from the rotating casing and delivers to the source of suppl the inlet to the said last named element being located at the position in said rotating casin at which the liquid surface is to be maintained, and the third element drawing liquid from saidrotating cas ing and delivering to said conduit.

27. In a, pump having a casing, a rotor eccentrically operating in said casing, a valve operated by direct connection with said rotor, and controlling independently the intake of oil and air to said casing, means within said rotor for controlling the discharge of the oil and air from the casing, and supporting means for therotor.

28. A pump having a cylinder, a rotor eccentrically operating in said cylinder, a valve operated by direct connection with the rotor and separately controlling the intake of oil and air to said cylinder, means within the rotor controlling the discharge of the oil and air from said cylinder, and a casing enclosing said pump. 29. In an apparatus of the character described, a rotatable casing for whirling a ring of oil contained therein, a scoop supported in said casing with one end directed against the path of the whirling oil for collecting oil, a valve in the path of the oil discharged from said scoop, and automatic ring of liquid.

means for maintaining a uniform supply of oil in said casing.

30. In a rotary air-pump, a rotatable casing, an impeller eccentrica 1y mounted to ro- 5 tate insaid casing, said casing having a central air inlet opening formed therein, and air-discharge conduit-means extending through said inlet opening and communicating with said impeller. 31. In a rotary pump of the class described, a rotatable casing for revolving a ring'of sealing fluid, a rotatable wheel eccentrically mounted in the casing so as to dip into the fluid, and means for adjusting the eccentricity of the wheel in 'the casing sons to vari the depth of submergence. of the wheel in t e fluid and thereby control the displacement of the pump. 7 '32. In a rotary pump, a rotatable casing, a

rotatable wheel eccentrically mounted in the casing; means for rotating the casing, and a connecting-rod for transmitting rotation from the casing to the wheel.

33. In a rotary pump, a rotatable fluidtight casing, a rotatable wheel in the casing, mechanical means for rotating both casing and wheel in the same direction at the same angular velocity'so as to minimize friction l in the pump. I

p 34. In an ap aratus of the character'deof the position ofsaid end of and scribed, the com ination of a casing for holding a rotating body of oil therein, a discharge scoop supported in said casingwith one end directed against the path of e rotating oil for eollectin oil, adjusting means for movin said end'o said scoo in order to'oontro the discharge of oil rom said and means for maintaining a subetant' y uniform amount of oil .inaaid irrespective WM. nouonas can 

